Highlights » EnviroAir furnishes a Coreco Model SR-0.5 Sand Reclaimer » Case Study: Coreco Model SR-0.5 Sand Reclaimer
Case Study: Coreco Model SR-0.5 Sand Reclaimer
Foundry Sand Reclaimer
EnviroAir furnishes a Coreco Model SR-0.5 Sand Reclaimer for drying and reclaiming waste foundry sand. The Model SR-0.5 has a nominal production capacity of ½ ton per hour.
Waste foundry sand is fed to the input hopper. A sealed screw feeder feeds the sand at a constant rate from the input hopper into the rotary retort. Air that is required to remove moisture and oxidize the organic compounds enters the rotary hearth through a connection provided on the sealed screw feeder.
A natural gas fired burner located in the furnace shell fires along the outside of the retort. Within the rotary retort the sand is uniformly heated to a temperature between 1,200 °F and 1,500 °F. Lifters inside the rotary retort continually mix, lift, and drop the sand through the heated air that travels through the retort. Moisture on the sand is evaporated and organic contaminants on the sand are oxidized, without direct flame impingement on the sand.
Retort gases are collected by the retort exhaust hood located at the discharge end of the retort. These gases are discharged to a cyclone and dust collector which remove particulate from the exhaust air. The internal afterburner design of the foundry sand reclaimer achieves air quality compliance in most applications.
The hot, clean foundry sand exits the rotary retort and streams through a discharge chute into the rotary cooler drum. In the rotary cooler drum, heat from the sand is transferred to the cooling air that is flowing through the cooling drum in the opposite direction. The counter flow air is draw through the cooling drum, into the cooler transfer hood located at the entering side of the cooling tube, and finally into the cyclone and dust collector. Since air travels from the discharge end of the cooling tube back towards the cooling transfer hood, fines are prevented from being discharged into the room.
The temperature of the sand leaving the cooling drum is between 10 °F to 30 °F above ambient temperature. As the reclaimed sand leaves the cooling drum, it is filtered through a 20 mesh screen. Metal and other rejected material greater than 20 mesh flow over the filter screen and exit the cooling drum, where they can be collected in a container or transferred by a conveyer. Approximately 95% of the waste foundry sand is reclaimed. This sand is generally cleaner than new sand and results in improved casting quality. The 5% sand that is lost during the reclamation process is free of organic contamination and is collected in the cyclone and dust collector.
The operating costs of the system are about $5.00 per ton of sand reclaimed based on 1.3% LOI, natural gas cost of $6.50 per MMbtu, and electrical cost of $0.08 per kWhr. Five other standard models are available with capacities ranging from ½ to 5 tons per hour.
You can read more about thermal sand dryers, view our complete line of Coreco products, or contact us to discuss your specific application and requirements.